The present invention relates generally to barcode scanners, and, more specifically, to different orientations thereof.
In one type of conventional barcode scanner, a laser, multi-faceted spinner, and a plurality of pattern mirrors are mounted inside a housing. A deflecting mirror is optically aligned between the laser and the spinner for directing a laser beam from the laser against the rotating spinner facets which in turn reflect the beam forwardly onto the pattern mirrors which produce a plurality of scan lines in a typically intersecting pattern for each revolution of the spinner.
The scan pattern is projected through a window toward a barcode typically found on the label of a consumer product, for example. The scan beam is reflected from the barcode with varying intensity due to the light and dark lines of the code which may then be decoded. The return beam passes through the scanner window in a reverse path along the pattern mirrors and spinner and is then reflected off a collection mirror, which typically surrounds the deflecting mirror, which focuses the return beam onto a suitable photodetector. An electrical processor is joined to the detector for decoding the return beam from the barcode in a suitable manner.
But for the spinner whose facets rotate during operation, the other mirrors of the scanner are stationary in a fixed interrelationship for producing the desired scan pattern. The scan pattern typically includes groups of parallel intersecting scan lines covering a useful area of projection over a barcode presented therein. The desired exit angle of the scan pattern through the scanner window is dependent upon the scanner application.
In one application, the scanner window is mounted horizontally and flush in the surface of a counter in a pass-through scanner configuration. This configuration is typically found in supermarkets which allows a clerk to pass individual products over the window for decoding the barcodes thereon. In this configuration, the exit angle of one of the scan lines at the midpoint of the scan pattern is about 45.degree. from the window in the upstream direction from which the products are presented. The remainder of the scan pattern spreads plus and minus a few degrees from the nominal 45.degree. exit angle. In this way, maximum accuracy in decoding presented barcodes is obtained.
However, in another typical application the scanner window is mounted vertically or normal to the top of the counter in a presentation scanner configuration. The midpoint scan pattern exit angle is preferably closer to 90.degree. which is perpendicular to the scanner window and generally parallel to the countertop. The scan pattern also has a suitable spread of several degrees plus and/or minus. In a presentation scanner, a product including a barcode is presented in front of the vertical window for decoding.
In view of the different horizontal and vertical applications of barcode scanners, different exit angles for the scan beams are required, which in turn requires a correspondingly different fixed orientation of the pattern mirrors inside the scanner. Different scanner models must therefore be manufactured which correspondingly increases associated costs of manufacture and use depending upon the required application.
In one compromise for providing a dual purpose barcode scanner, a scanner specifically configured for the horizontal, pass-through application may be simply converted to the vertical presentation application by the use of a simple change in mounting fixtures therefor. However, the exit angle of the scan pattern remains the same, for example 45.degree. to the window, even though the window is mounted vertically instead of horizontally. This decreases the efficiency of presenting barcodes in front of the window, since 90.degree. is considered optimal.
An example of such dual use barcode scanner has been commercially available for many years from the NCR Corporation of Ohio under the basic model 7880, with suitable mounting kits being provided therefor for use in the pass-through or presentation applications. The basic configuration of the NCR model 7880 barcode scanner is disclosed in U.S. Pat. No. 5,591,954. In this model, eight pattern mirrors are symmetrically mounted adjacent to a four-faceted spinner for producing a corresponding scan pattern with a mid-point scan pattern exit angle of about 45.degree. with a corresponding spread of plus or minus several degrees relative thereto.
It is desired to improve this basic barcode scanner for dual use in either pass-through or presentation type scanner applications, with an improved scan pattern exit angle in the presentation configuration.